Moderately severe chronic airflow obstruction. Can corticosteroids slow down obstruction?

In a former study in patients with severe chronic airflow obstruction (CAO), (forced expiratory volume in one second (FEV1) ranging from 350-910 ml), we concluded that daily oral corticosteroids might slow down the progression of disease. The results of the present long-term (14-20 yr) study on 139 non-allergic patients with less severe CAO (FEV1 greater than or equal to 1200 ml, FEV1 as a percentage of vital capacity (FEV1%VC) 40-55%) confirm and extend our former observations. Four patterns of the course of FEV1 and inspiratory vital capacity (VC) in time were recognized: 1) linear decrease; 2) no change; 3) initial increase, followed by decrease; 4) initial decrease, followed by increase. Groups 1 and 3 had a higher functional residual capacity as a percentage of total lung capacity (FRC%TLC) as compared to group 2 and 4; the work of breathing was lower in group 2 than in the other three groups. Otherwise the initial 82 parameters, including the degree of reversibility of airflow obstruction and smoking habits were comparable in the four groups. The four patterns of FEV1 showed a strong association with the long-term use of prednisolone. When oral prednisolone was instituted or increased to a dose of at least 10 mg/day continuously, FEV1 either remained constant, decreased more slowly or even increased over many years of follow-up. When the oral dose was diminished to below 10 mg/day, FEV1 decreased.(ABSTRACT TRUNCATED AT 250 WORDS)